A cobpobation



7 July 31, 1928. 1,678,717

M. ALDEN ELECTRICAL APPARATUS Filed Jan. 17, 1927 v 3 Sheets-Sheet 1 M. ALDEN ELECTRICAL APPARATUS July 31, 1928. I 1,678,717

Filed Jan. 17, 1927 I 3 Sheets-Sheet 2 INVENTOR July 31, 1928.

. M. ALDEN ELECTRICAL APPARATUS Filed Jan. 17, 1927 a Sheets-Sheefi s R O. T N E V N Patented July 31, 1928.

UNITED- STATES PATENT OFFICE.

amazon ALDEN, or armor-man, uassacnusnr'rs, as'srcnon T man armamroams comm, or nnocx'ron, massacnusnrrs, a conrom'rrou or messa- CEUSETTS.

I ELECTRICAL APPARATUS.

a lication and January 17, 1927. Serial no. 1e1,a1e.

One object of my invention is to produce an audio frequency amplifier havlng extremely faithful reproduction characteristics.

Another object 1s to produce an amplifier having uniform response over a broad band of fre uencies and more particularly at the lower equencies.

Another object is to produce a high quality amplifier which may be readily attached to existing radio receivers.

Still another object is to produce a device of this type which on account of certain constructional features later described may be readily produced in great quantities according to standard specifications and marketed at an extremely reasonable price.

There are today at least two important fields for a complete and reliable amplifier having high quality of reproduction. One

50 of these is the amateur set constructor and experimeter who may be frequently altering his radio frequency circuits as each socalled new circuit comes to light but who would be greatly pleased to be able to purchase a complete wired audio amplifier of thebest type for use with his various tuning-and radio frequency amplifyinglcircuits.

The second field comprises the undreds of thousands of owners of receivers in which the sensitivity and selectivity of the radio fre uency and demodulation circuits are per ectly satisfactory but in which the quality of reproduction of the audio frequency 'circuits is far below the present standard.

An amplifier of the type described which may be bought at a moderate price and is readily attac able to these existlng receivers without the use of tools and which will bring these receivers -up to or above the present standard of reproduction is a distinct contribution to the art.

Referring to the drawings Fig. 1 1s a plan view of one embodiment of my invention.

Fig. 2 is a side elevation and Fig 3 is an end elevation of the same embodiment.

Fig. 4 is a fractional plan view of the same embodiment after the sealin compound had been poured in but be ore the Fig. 6 is a schematic wiring diagram of the preferred circuit for use in this device.

Fig. 7 is an exploded perspective of the parts of my device.

Fig. 8 is a transverse vertical section of the same embodiment. I

The cover plate 10 may preferably be molded as shown in the sectional view Fig. 8 and may have flanges to embrace the sides of the container 11 so as to insure alignment. Beneath this cover plate 10 is mounted the insulating strip 12 carrying the combined resilient contacts and terminals, such as, 13, 14, 15 and 16. The contacting parts of these members project into the apertures as 17, 18, 19 and 20 which apertures register with the a ertures 17', 18', 19' and 20' in the top p ate 10. These apertures register with the pron of a vaccum tube, and with their associa combined contacts and terminals form a socket assembly for a vacuum tube. One form of this str1 or multiple socket cpnstrizlction is describedd1 at length and c aime in m co 'n a lication #137,286. y pen g H) A rheostat 21 to control the cathode heat may be rovided and may have the operating han le 21'. A terminal cable 22 is provided for making suitable connections with the cathode, anode, and biasing batteries. Lead 23 is provided with some suitable connector structure, such as, 24 for insertion between the detector tube 25 and its socket in the receiving set (not shown;l or a connector may be thus employed suc as that described in my copending application No. 139,656. Pin jacks 26, 27 and 28 are provided to afford connection with the tips of the loud speaker cord (not shown).

I prefer to use the amplifier system shown schematically in Fig. 6 and described in the copending application of H. P. Donle No. 141,998. Thls is a combined transformer and capacitative coupling system, but it should be understood that any system of amplifier coupling either radio or audio frequency may be employed without departing from the spirit of the invention herein claimed.

' An output choke is shown at 29 and an output'condenser at 30 which prevent the direct current of the anode circuit from flowing through the loud speaker when it is plugged into the pin jacks 26 and 27. If a type of loud speaker is used in which it may be desirable to have a direct current component in its input current the pin jacks 26 and 28 are used.

Referring more particularly to Fi s. 5, 7 and 8 the container 11 may be pre erably formed of sheet metal and may be suitably finished as with a crystalline lacquer. In the bottom of said container are laid the coupling transformers 36, 37 and 38 and their associated condensers 36', 37 and 38 which are preferably mounted so that they lie tangent to both windings of their associated transformer and are held in place by an overall binding of paper or other suitable material.

The output choke and condenser 29 and 30 are also laid in the bottom of the container as shown.

A terminal board 40 which may be unched out of impregnated cardboard, thin her or other suitable insulating material is provided with a series of apertures some of which, such as 41 and 42, are to pass such wires as are connected from the coupling devices to the contacts carried by the strip 12 and some of which, such as 43, are rovided with eyelets or tubular rivets, suc as 44, which anchor the conductors of the terminal cable 22 and these eyelets also serve as terminals for such other leads as are connected to the conductors forming said cable and as points of connection for such leads have common connection. I

Letters or numerals designating the names of the leads, which are associated with the apertures or eyelets in the terminal board 40, maybe printed adjacent to said eyelets or apertures. 1

In assembly, the leads from the coupling devices are threaded through their associated apertures or eyelets and the terminal board 40 is then lowered into the container 11 so as to rest or nearly rest upon the couplin device.

T e terminals of the conductors of the cable22 have already been crimped under their respective eyelets. Such connections from the lower part of the structure as are to terminate at the terminal board 40 are scraped and soldered to their re ective eyelets as at 45. The contact balding strip 12 is then placed close to the terminal board 40 and the remaining connections made. A suitable insulating wax or rosin 50 is then poured into the container until it covers or submerges the terminal board 40 and is allowed to cool. The remaining assembly which consists of securing the contact carrying strip 12 and the cover plate 10 in place is now com leted.

The con ing units are held in the container by t e insulating material 50 and require no mounting devices, such as, clamps, screws, bolts, etc. and are at the same time to hold various leads apart and in their proper place and to help identify them durmg connection and assembly.

It will be understood that the holes for the wires and eyelets or other rivets will be punched or otherwise formed according to some predetermined plans to facilitate connections at the proper points without danger of error.

The cover assembly serves not only as a multiple socket for such number of tubes as may be required but also to support the reproducer jacks as well as the regulating device 21.

It should be noted that a very simple and easily manufacturable amplifier is thus secured by the three plane method of wiring employed by me.

I claim:

1. An amplifier set com rising a casing, a coupling. device moun therein, a cover member secured thereto and including a socket having contacts for a vacuum tube, an insulating conductor positioning plate between said coupling device and said socket, a cable having conductors riveted to said plate, some of said contacts being connected to the rivets and other wires connecting other contacts with the coupling device.

2. An amplifier unit comprising a casing, coupling devices sealed in t e casing, an insulating strip secured to said casmg and carrying contacts for the prongs of vacuum tubes, an insulating partltion between the cou ling devices and the contact carrier, a cab e having conductors secured to the partition, said coupling devices having wires connected to said conductors at said partition and other wires passing through said partition to some of said contacts.

3. A coupling device comprising a casing having a base and walls, a cover for said casing having a pluralit of sockets for holding vacuum tubes said sockets having means for contacting with the prongs of said tubes, terminal cables for connection with associated apparatus, coupling devices within said casing, and an insulating planar structure between said coupling units and said cover, said structure being provided with apertures through which are passed leads connectin a number of said contacting means with sald coupling devices and said structure being also provided with tubular rivets which serve as anchors for said terminal cables and as means for connecting asing the proper electrical associatlon of the sociated leads'.

4. An amplifier comprising a casing, coupling devices mounted therein in predetermined positions an insulating partition cons'tituting an anchorage and positionin memher, a cable having leads secured to said partition at predetermined positions, said partition having passage at redetermined positions for leads from said coupling devices,

and a socket assembly having contact members and constituting a cover for said casing, said contact members bein connected to the leads from said coupling devices and to said cable.

5. An amplifier construction consisting of apparatus mounted in three planes, the upper plane comprising tube contacting and tube controlling apparatus, the lower plane comprising inter-tube coupling apparatus, and the intermediate plane comprising template apparatus having connection arranged according to a predetermined plan for efiectvarious elements of the upper and lower planes of the construction. v

-6. Aradio coupling unit com risin acasing, coupling devices moun in t e bottom thereof, an insulatin template above said coupling devices having passages punched 1n said template according to a predetermined plan, an insulating top plate or said casing having connections r external devices, sa d connections being arranged according to predetermined plan,

said coupling devices having leads passing through certain predetermined passages in said template, some of said leads being connected'to certain of said connections on the top plate and a cable havinlg wires connected to the remaining leads at t e other passages in said template.

' MILTON ALDEN. 

